Crate char_ranges

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Expand description

Similar to the standard library’s .char_indicies(), but instead of only producing the start byte position. This library implements .char_ranges(), that produce both the start and end byte positions.

Note that simply using .char_indicies() and creating a range by mapping the returned index i to i..(i + 1) is not guaranteed to be valid. Given that some UTF-8 characters can be up to 4 bytes.

CharBytesRange
'O'10..1
'Ø'20..2
'∈'30..3
'🌏'40..4

Assumes encoded in UTF-8.

Example

use char_ranges::CharRangesExt;

let text = "Hello 🗻∈🌏";

let mut chars = text.char_ranges();
assert_eq!(chars.as_str(), "Hello 🗻∈🌏");

assert_eq!(chars.next(), Some((0..1, 'H'))); // These chars are 1 byte
assert_eq!(chars.next(), Some((1..2, 'e')));
assert_eq!(chars.next(), Some((2..3, 'l')));
assert_eq!(chars.next(), Some((3..4, 'l')));
assert_eq!(chars.next(), Some((4..5, 'o')));
assert_eq!(chars.next(), Some((5..6, ' ')));

// Get the remaining substring
assert_eq!(chars.as_str(), "🗻∈🌏");

assert_eq!(chars.next(), Some((6..10, '🗻'))); // This char is 4 bytes
assert_eq!(chars.next(), Some((10..13, '∈'))); // This char is 3 bytes
assert_eq!(chars.next(), Some((13..17, '🌏'))); // This char is 4 bytes
assert_eq!(chars.next(), None);

Example - DoubleEndedIterator

CharRanges also implements DoubleEndedIterator making it possible to iterate backwards.

use char_ranges::CharRangesExt;

let text = "ABCDE";

let mut chars = text.char_ranges();
assert_eq!(chars.as_str(), "ABCDE");

assert_eq!(chars.next(), Some((0..1, 'A')));
assert_eq!(chars.next_back(), Some((4..5, 'E')));
assert_eq!(chars.as_str(), "BCD");

assert_eq!(chars.next_back(), Some((3..4, 'D')));
assert_eq!(chars.next(), Some((1..2, 'B')));
assert_eq!(chars.as_str(), "C");

assert_eq!(chars.next(), Some((2..3, 'C')));
assert_eq!(chars.as_str(), "");

assert_eq!(chars.next(), None);

Structs

  • CharRanges
    Note: Cloning this iterator is essentially a copy.

Traits